Thermometer



H. B. BROWN Feb. 4, 1947.

THERMOMETER I Filed June 28, 1944 14' u I I 15 1 29.10

r H B BROWN Patented Feb. 4, 1947 ENT OFFICE THERMOMETER H. Brainard Brown, Rochester, N. Y., assignor to Taylor Instrument Companies, Rochester, N. Y., a corporation of New York Application June 28, 1944, Serial No. 542,474

2 Claims. (01. 73-276 This invention relates. to a thermometer.

In the past, it has been the practice to fasten the glass stem of a thermometer to a thermometer back by means of pieces of wire or metal band which encompass the thermometer stem. These pieces, after being inserted through holes in the scale plate, are bent to engage the back of this plate. Such fastening means have exposed ends which catch on cleaning cloths or the like. Also, where such bands are used, it requires a skilled operator to produce an acceptable prodnot.

The main feature of the present invention relates to thermometers wherein thermoplastic clasps are fromed to embrace the thermometer stem and to eng e the rear surface of the thermometer plate.

Another feature of the invention relates to a thermometer utilizing a clasp which has no part crossing the path of the indicating column of the thermosensitive liquid and yet securely retains the thermometer on its graduated scale plate.

In the drawing, Fig. 1 is a front view of the finished thermometer of the present invention and Fig. 2 is a side elevation thereof; Fig. 3 is a View of an extruded or molded strip of thermoplastic material having the outline of a clasp from which individual clasps can be cut; Fig. 4 shows an individual clasp cut from the strip of Fig. 3; Fig. 5 is a section through a thermometer stem and scale plate with one of the clasps in assembled relation thereon, prior to the operation of forming the clasp to embrace the scale and the stem; Fig. 6 is a sectional view illustrating heated tool parts in operative relation to the assembled thermometer stem, clasp and scale, with portions of the clasp shown formed, under heat, to embrace the several parts; Figs. 7 and 8 are, respectively, a front View and a side View of a thermoplastic bulb guard assembled on the scale plate prior to being anchored thereon; and Figs. 9 and 10 are similar views showing the guard after being attached to the scale plate by upsetting a part of the guard while it is heated.

Referring especially to Figs. 1 and 2, the thermometer comprises a scale plate 5 on the front of which there is mounted a stem 6 of a glass thermometer which terminates in a bulb I. The bulb and part of the stem are filled with a thermosensitive liquid 8 such as mercury or an organic liquid. The thermometer stem is retained on the scale plate by means of clasps 9 anchored in apertures in the plate at the upper and lower ends of the stem. Each clasp, which is made of thermoplastic material, comprises a pair of forr i i 1 2 wardly extending fingers l l adapted to be shaped under heat and pressure to embrace the sides of the thermometer stem. In addition, each clasp is provided with a shoulder 12, to engage the front of the plate and with a preferably notched projection l3 adapted to be inserted through the mentioned aperture in the scale plate, after which parts of this projection are upset to secure the clasp on the scale plate. A bulb guard of thermoplastic material 14, is mounted on the scale plate to extend in front of the bulb l. The guard is preferably molded from thermoplastic material to have the notched portions l5 adapted to be received in spaced openings adjacent the thermometer bulb and thereafter upset, as shown in Figs. 9 and 10.

In assembling a thermometer according to the present method, each clasp 9 is preferably cut from a strip l6 of thermoplastic material extruded or molded into the general shape illustrated in Fig. 3, it being understood that the strip is out along the several dotted lines to provide a number of individual clasps 9. Two clasps 9 are used to anchor the stem on the scale plate by inserting the projection I3 of each clasp through an opening in the scale plate, with the shoulder l2 engaging the front of the plate. The thermometer stem is then placed between the fingers ll of each of the two clasps. The next step in the method comprises applying a heated tool l8 to the rear surface of the scale to heat and upset the notched projection l3, while applying the spaced heated bars I9 having their inner surfaces slightly curved to embrace the fin-- gers ll, thereby heating and shaping these fingers to the shape indicated in Fig. 6. The notched portion IS on the bulb guard it may likewise be heated and thereafter upset in like manner to engage the rear surface of the scaleplate.

The present construction is well adapted for rapid production of thermometers without the use of skilled operators. Furthermore, the clasps have no parts which catch on cleaning cloths and yet they securely retain the thermometer stem on the scale. In addition, since'the fingers of the clasp do not cross the face of the stem, the indicating liquid column in the stem is not obscured.

I claim:

1. A thermometer comprising a scale plate with spaced openings therein, a thermometer tube including a capillary stem and bulb communicating with said stem, said thermometer tube containing a thermosensitive liquid, and thermoplate deformed and gripping the sides of said stem.

2. A thermometer comprising a scale plate with spaced openings therein, a thermometer tube including a capillary stem and bulb communicating with said stem, said thermometer tube containing a thermosensitive liquid and thermoplastic clasps anchoring said thermometer tube tosaid plate, each clasp having a shoulder engaging the front of the plate adjacent an opening and a projection passing through said opening with the free end of the projection upset and engaging the rear surface of the plate, said clasp also having a pair of spaced f ngers extending directly outward from the front of the plate with the outer 4 end portion being bent against the stem and gripping only the sides of the stem but not the front thereof whereby the liquid in the stem is not covered,

H. BRAINARD BROWN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,612,364 Ely Dec. 28, 1926 2,021,283 Bolton Nov. 19, 1935 2,037,194 Curtin Apr. 14, 1936 02,326 Sadler Oct. 17, 1905 1,377,578 Harris May 10, 1921 1,670,385 ,Schawcr0ss May 22, 1928 FOREIGN PATENTS Number Country 7 Date 568,998 French Jan. 3, 1924 

